function bar() {
    var myName = "Fog";
    let test1 = 4;
    if (1) {
        let myName = "xxx";
        console.log(test); // 1
    }
}
function foo() {
    var myName = "Barry";
    let test = 2;
    { // 块级作用域
        let test = 3;
        bar();
    }
}
var myName = "Fogx";
let myAge = 18;
let test = 1;
foo();